Big Heads

[Giff]

Does anyone know who or what determines the diameter of screw heads. It doesn't seem to have anything to do with the screw size. I am using some screws supplied with hinges, which aren't very good. They are s/s screws that have a c/s head. I have tried to substitute the same size 3.00mm x 25mm with a KTX Concept screws but the head is much bigger and won't fit the c/s. I have also tried a Spax, better but still too big. All these heads fit a PS1 bit but vary a lot in head diameter. Is head size listed anywhere or does anyone know of small heads ? Geoff

 

[kostello]

If you are using piano hinges you need piano hinge screws......

screw-size-piano-hinge-t34734.html

 

[o0dunk0o]

Wood screw gauges are determined by head size, basically you measure the head in 16ths of an inch minus 1 then double,

If the head measures 1/4 that equates to 4 sixteenths
4 minus 1 is 3
3 doubled is 6 therefore its a #6 screw

daft I know but then again isn't every imperial measurement

 

[Giff]

I sort of understand that but can't understand why two different makes of 3.00mm ( imperial 6 ) screws have different sized heads.

 

[Gromit62]

Further to o0dunk0o’s answer the conversion to metric is as follows:
Imperial Metric
No 4/5 3.0
No6 3.5
No 8 4.0
No 10 5.0
No 12/14 6.0
Gleamed this from a Good Woodworking Chart which I have used for quite a long time now.

 

[o0dunk0o]

Ctx concept screws always had daftly big heads, I've never got on with them tbh,
spax screws tend to be pretty reliable for head sizes although they do have a 2 stage countersink head that doesn't sit well in countersinks.

I always try to use traditionally cut screws for hardware, they just work better.

just a side thought the hinge might have been supplied with #5 screws depending on the maker

 

[Giff]

That link to the "hinge screws" seems to be the answer. I didn't realise that they existed and answers the question. Thanks for the replies and help. Geoff

 

[Shrubby]

You could adjust the countersink hole to suit your screws. I use G&J Halls contersinks - the smallest XCM06 will fit into tiny hinges without damaging the knuckle (made in England and reasonably priced too)
Matt